only verify the prekey id when there is no current session active

libtextsecure/message_receiver.js

@@ -731,6 +731,7 @@ MessageReceiver.prototype.extend({
         window.log.info('prekey message from', this.getEnvelopeId(envelope));
         promise = captureActiveSession(sessionCipher)
           .then(async () => {
+            if (!this.activeSessionBaseKey) {
               try {
                 const buffer = dcodeIO.ByteBuffer.wrap(ciphertext);
                 await window.libloki.storage.verifyFriendRequestAcceptPreKey(
@@ -741,6 +742,7 @@ MessageReceiver.prototype.extend({
                 await this.removeFromCache(envelope);
                 throw e;
               }
+            }
             return this.decryptPreKeyWhisperMessage(
               ciphertext,
               sessionCipher,